In many medical procedures, various physiological conditions present within a body cavity need to be monitored. These physiological conditions are typically physical in nature—such as pressure, temperature, rate-of-fluid flow, and provide the physician or medical technician with critical information as to the status of a patient's condition.
One device that is widely used to monitor conditions is the blood pressure sensor. A blood pressure sensor senses the magnitude of a patient's blood pressure, and converts it into a representative electrical signal that is transmitted to the exterior of the patient. For most applications it is also required that the sensor is electrically energized.
Some means of signal and energy transmission is thus required, and most commonly extremely thin electrical cables are provided inside a guide wire, which itself is provided in the form of a tube which often has an outer diameter in the order of 0.35 mm, and oftentimes is made of steel. In order to increase the bending strength of the tubular guide wire, a core wire is generally positioned inside the tube. The mentioned electrical cables are then positioned in the space between the inner lumen wall and the core wire.
A sensor guide wire assembly in accordance with a conventional design generally comprises different sections, such as a male connector, a shaft region, a flexible region, a sensor region and a tip region.
As is generally known in the art, the mechanical properties (e.g. flexibility and strength) of the sensor guide wire will mainly be determined by the design and dimensions of the core wire, and the materials used in the different sections of the guide wire.
It has been proved to be advantageous to use stainless steel or a super elastic alloy, such as Nitinol (NiTi), in the manufacturing of the different parts of the guide wire.
For example, EP1475036 A1, discloses a guide wire wherein the core wire is made from stainless steel or Nitinol.
However, a problem arises when it is desirous to join sections of a guide wire made from different materials, for example one section from stainless steel and another section of the guide wire made from Nitinol (NiTi), due to the fact these two materials are non weld-compatible metals. The difficulty of joining the different materials by welding results in that the joints between the different parts or regions of the guide wire becomes unreliable. Thus, the joined sections will not be securely fastened to each other.
The object of the present invention is therefore to provide a secure way of joining sections of a guide wire made from different non weld-compatible metals
The object is also to facilitate the assembly of the different parts of the sensor guide wire.